Not exact blocks but discouraging users from clicking affiliate links: When a user clicks a link, the AVG alert box appears. Webmasters at other forums and blogs are discussing this, have you experienced this? This may be due to
http://www.avg.com/us-en/press-releases-news.ndi-224945 link scanner. This appears to be happening to Mainstream affiliate networks. Some claim that its due to 'suspect' programs within the affiliate network like CJ, etc.
FYI